DESCRIPTION: The HER2/neu oncogene appears to play an important role in the initiation and progression of many types of human cancer, including approximately 25 percent of non-small cell lung cancer (NSCLC), the leading cause of death in both men and women in the U.S. The overall goal of this project is to find novel ways to specifically inhibit HER2/neu expression by developing oligonucleotide (ODN) - chlorambucil (CHL) conjugates that will bind in a site-specific manner to the HER2/neu gene by triplex DNA formation and lead to DNA alkylation at specific guanine bases by the CHL. Specifically, the work outlined in this application will accomplish the following goals: 1) Characterize the ability of chlorambucil-conjugated beta (natural) and alpha (nuclease resistant modification) anomeric ODNs to diret site-specific DNA alkylation in the HER-2/neu gene; 2) Characterize the ability of chlorambucil-conjugated ODNs to bind to the HER/neu gene and inhibit HER-2/neu gene transcription elongation in vitro and in a cDNA expression plasmid transfected into HeLa cells and NIH3T3 cells; 3) Demonstrate ODN binding and site-specific DNA modification in the chromatin of living NSCLC cells that express the HER-2/neu gene; 4) Characterize the ability of adenoviruses to mediate ODN uptake and nuclear localization in NSCLC cells when adenovirus-ODN complexes are formed with a chemical linker. 5) Determine the ability of optimally delivered ODN-CHL conjugates to inhibit HER-2/neu gene expression and reverse the malignant phenotype in tissue culture and rodent models of human NSCLC. The specific objectives of this application are designed to address the major obstacles to the successful development of an ODN-based site-specific DNA binding drug. The successful completion of these Specific Aims will lead to invaluable insights into the design of gene-specific DNA binding compounds. The development of a HER-2/neu gene specific anti-gene compound will provide a great deal of information about the role of the HER-2/neu gene in the initiation and progression of NSCLC and may lead to novel treatment approaches for HER-2/neu gene expressing cancers such as NSCLC.